In today's modern society where there is a wide use of the mail system for sending substantially the same letter to a large number of different addressees, there is a need for replicating an actual signature on each letter in order to enhance the credibility of the letter. On the other hand, it would be nearly impossible for the sender of the letter to sign literally thousands of such letters. For example, heads of large organizations or companies often send letters to each of their employees or members, respectively, and like to have the personal touch of an actual signature. Similarly, members of Congress send out large numbers of letters to their constituents and if they had to sign each letter, they would spend a large part of their time doing nothing but signing the letters. Other uses would be in the advertising field by, for example, charitable organizations soliciting contributions, or companies advertising their products through the mails.
With the modern age of computers and multiple printers, a large number of individually typewritten letters can be mass produced. Such letters would largely loose their effectiveness unless they were "signed" with an authentic signature. In addition, occasionally there is the desire to handwrite a postscript to the letter below the signature. Obviously, the time requirements for such activity could be prohibitive to the sender.
This problem has been solved, to some extent, by prior art machines which are basically analog devices that "trace" a previously written signature. While these analog machines have generally proven to be satisfactory, they do have a number of drawbacks and disadvantages. For example, they tend to be extremely heavy, and thus not readily portable. Secondly, the machine is fairly limited to a simple signature and thus could not be used also to "handwrite" a message in the form of a note or postscript to a typed letter. Furthermore, these machines are fairly singular in their use, thereby requiring a relatively large capital expenditure for a singular use. Other disadvantages include the difficulty in providing, on the one hand, security and, on the other hand, easy accessibility by authorized persons and easy reproduction of any one of a plurality of signatures or handwritten messages.